Clothes dryer condensing system



y 5, 1964 s. L. MCMILLAN 3,132,005

CLOTHES DRYER CONDENSING SYSTEM Filed March 13, 1961 Jul Em STEPHEN L. MMILLAN ATTORNEY CLOTHES DRYER CONDENSING SYSTEM Stephen L. McMillan,Wheaten, IlL, assignor to General Electric Company, a corporation of NewYork Filed Mar. 13, 1961, Ser. No. 95,107 4 Claims. (Cl. 34-54) Thepresent invention relates to clothes dryers which include a closed cyclecondensing system and more particularly to an improved construction and'control of the condensing system.

It is therefore an object of the invention to provide an improved andsimplified condenser construction and control system. for a clothesdryer.

It is a further object of the invention to provide in a closed" cyclecondenser dryer system, a dual purpose high temperature thermostat whichresponds either to malfunctioning of the heaters or to an overflow ofliquid in its condenser chamber. I e

It. is a further object to provide a simplified shut-off mechanism for adryer, whichresponds to an overfill of liquidiinithe condensing chamberof a clothes dryer to stop tlie dryer operation. It is; known that in acondensing clothes dryer, a heated lair how is used to evaporatemoisture from the clothing, and subsequently the moisture is condensedfrom the air by means of cool water which is introduced into contactwith the heated air within the dryer cabinet. The resultant, liquid isdischarged to drain either by gravity or by a" pump. Itwill beapparentthat" should the outlet drain or the pump become clogged, the continuedflow ofcondensing water could flood the clothes dryer with obviousundesirable results. e v I To alleviate this difficulty in a watercondenser clothes dryer or the like; the present invention contemplatesa li'quidcontrol means wherein a control circuit is provided incombination with circuit interruptingmeans responsive toa predeterminedliquid level in thecasing or container for the liquid, whereby theoperating circuit for the dryer is' rendered inoperative should theliquid in the casing or container reach a predetermined level because ofclogging ofthe discharge opening therefor; or failure of the pump, ifsuch be used in the apparatus.

'I he'circuit [interrupting means utilized as the preferred controlherein is the thermostat common to clothes dryers as the hightemperature thermostat required by most safetyicodes to interrupt atleast the power to the heating element in the circumstance ofunduly.high tem pera t ure s. The thermostat in addition to its normal usecontrols the maximum condenser water level in that the air whichiscirculated over-the heaters to extractlheat therefrom and maintainthem at. a safe operating temperature is channeled through thecondensing chamber. The chamber is so constructed that an excessivequantity, of liquid in the condensing chamber willshut off the air flow;consequently the heaters will overheat and the thermostat will operateto open the power circuit.-

To be more specific about. the constructionof, the condenser chamber,the condensing chamber includes one Qlf more baffles forcing the airflow into a serpentinep'ath'. Them a'in bathe depends from the chamberceilingto-a predetermined height.

the chamber reaches this. height, an elfective barrier totheflow-.of'air. is formed by the combination of bafile and water below it.This barrier will tend toblock or interrupt theflow. of air totheheaters, whereupon the heaterswill, as mentioned, overheat andtripthehigh tempera ture thermostat. In the preferred circuit combination,the tripping of the thermostat will open the circuitsto the dryer drivemotor, the timer motor, the air heaters and,

the water inlet control and as a result the dryer will bedeenergizedpending a manual resetting of dryer control mechanism.

It should be noted that the machine operatormay reset the dryer withoutcorrecting thefault and operation be resumed the thermostatheatssufiiciently to re-open the iopenative circuits. Persistenceihrestarting object.

The invention both as to itsorganization and principle;

, along the line'2-2 of PEG. 1;

lower right" corner of would conceivably cause the machine to overflow;however, the shut-oh level in the condenser chamber {may be so relatedto the capacity of the chamberthat' shutoff will occur at but a fractionof the capacity of the condensing chamber; It is a further feature ofthe invention that the co'ndensing chamber is'constructedtoallow readyaccess to its interior for the purpose of freeing" the drain by removalof the obstructing material or of operation, together with furtherobjects and'advan-' tages thereof, will best be understood by referenceto the following specification '[flkI1lIl' 'COIlHCtlOI1 with theaccompanying drawings in which: I V V FIG'.'1 is a front perspectiveview of a clothes dryer. utilizing my invention with the outer wallsshownin outline and portions broken away; f F

FIG. '2 is a sectional side view of the dryer viewed FIG. 3 isa sideview inlcross section ing chamber; 1 v j FIG. 4 is' a schematic wiringdiagram of the control ortheec dens;

circuit incorporated in theid ryer of FIGS; 1- and 2; and

. FIG. 5 is a'partial'side viewas FIG; 2. shoWi'ngI-the door removed. iv j v Referring now detail to the-dryer 10 of F Ki s. 1' and 2',l thedryer there shown is of the type known'as Axial Flow. In dryers of thistype there is, an imperforate I walled cylindrical drum v12},journalledlto rotate-on a Whenthe level of water within" horizontal axiswithin a substantially imperforateQ appear-ance oahinet 14; The drumincludes. teamm te. perforations 16 about its rear wall 18 and aceritraluaccess opening 20 in-its front .wall..22; Adjacent andoutwardlyof the opening'20,.'thecabinet14 is ported with. a cabinet accessopening 24 which isnorrnally covered by: a side hinged. door 26. Door.2'6.is pivotal hetjween-sa closed position denyingaccess to. the-druininterior and: an open position allowing free entry to the drumiinterionto allow loading of the drum. 1

The dryershown, further is of-the reoircu-lator'ytype. which afloW'ofPair is heated, passed through "the drum under suction pressure irom ablower andpiassed through a v treating chamber for return-flowthroughvthe system. Within generally described systern there arepositioned a plurality of radiant heaters 30; which are secured to.anannular stationary plate 32*concentuie to and outwardly spaced fromthe reardrumwall. These heaters will heat air in circulation justpriorto; entry into the drum via thevinlet. perforations 16 in the drumrear wall. To exhaust lair fromthe there pro vided adjacent the drumfron-topening a downwardly directed duct 34 which serves to ohannelexhausted air to' the rotary blower 36. Airlis emitted suadiallyfromthe; blower to a. horizontal duct 38 which leadsimo onejend of theessentially reotangularcondensing chamber 40. At

. the opposite end of the condensingoharnber, .thereiis anexit air duct42 which is upwardly positionedto direct;

v the exit firom the condensing chamber-"past the-heatersfor'reciroulationto the drum. j 3

the dryee. there is provided a main drive meter SO mounted-toV theoabinet basestruotlire (not shown and whichby-ob; v-ious and generallyknown mechanical expedients such as; pulleys and the like rotates blower36, drum 12 and also the dryer with the trouble access r form a startingcircuit which restores on release of manual pressure and must be resetfor further operation once the circuit has restored. In series withtimer switch contacts 96 and door switch 98 is the high limit thermostat104 which nominally may be called the safety thermostat.

This thermostat remains closed at all temperatures below a high, safetemperature such as 260 F. This thermostat prevents excessiveoverheating of the machine and will open the operative circuits to themachine in any situation productive of this excessive temperature. Sucha thermostat will normally be set to re-open at a lower temperature suchas 220 F. The physical positioning of thermostat 104 may be seen in FIG.2 mounted to the flange of annular stationary plate '32 in the areaabove heaters 30. The thermostat will sense the temperature of air atthe heaters .and will rapidly respond to changes in air tem- 97 shortlybefore the cycle termination to allow a final,

non heated, non-condensing cool-down vperiod. During this'cool-downperiod, the timer controlled contacts remain closed allowing thedrum totumble for the re mainder of the preset time. V

' The operationof the invention has follows: The wet clothes to be driedare placed in dr-urn12, and door 26 is closed, closing door switchcontacts ,98. Knob 78 is rotated to the position indicating the cycleduration required This rotation of the knob closes contacts 92 and'96.Knob 78 is then depressed closing momentary contacts 102. Qlosure of'themomentary switch completes a 118 volt circuit to the drive motor and tothe timer motor. These motor starting circuits may be traced firotn leadN through the parallel paths including inthe first path start winding80and motor contacts 84, and

in the second path run winding 82 of the drive motor and-through thethird paral'lel path including the winding of timer mot-or 94; throughthe multipleconnectionto momentary contacts 102, door switch contacts98,

thermostat 1-04, and closed contacts 96 to lead L2. Drivev motor 50accelerates and tn'ps its centrifugal switch contacts 84, which opensthe circuit to the start Winding 80 and locks the run winding 82 over ahold path bypassing momentary contacts 1-02. Momentary contacts 102 thenrestore. The timer motor 94 and run winding 82 of the V 6 pump 64 which,as previously described, is operated by drive motor 50. I I

The comparatively dry ,air then passes under bathe 72, which optimallyextends for the full-width of the condensing chamber 40, and out airvent 74 for recirculation past heater and high temperature thermostat104 into the drum. This cycle continues until air temperature atthermostat 90 rises above the acceptable operating, and the thermostatopens its contacts to deenergize heater 30. The temperature drops andthermostat 90 reoloses its contacts. Thermostat 90 cycles the heaters inmanner for the entire timed period. At the conclusion of the heat dryperiod, timer contacts 92 and 97 restore; Contacts 92 open the heatercircuit, and cont-acts 97 restore the solenoid, 68' shutting off the howtonozzl'es 66. The motor continues tumbling the clothes for a cool downperiod after which timer 94 having completed its cycle opens contacts 98to deenergize timer motor 94 and the drive motor run winding Drive motor50 slows down and eventually stops its rotation. Contacts 84 and 86restore on slow down of the-motor and th circuit is thereby returned tonormal.

With a closed air flow system'as shown;- blockage of air flowdue to anycause, cause the heaters to overheat, there being no air circulated tocarry olfthe heat generated. As a result the temperature at the heatersmounts very rapidly. On this temperature rise, thermostat 104 operatesits contacts to the open position deenergiz-- ing the circuit to themotor winding. The drive motor slows down and opens speed responsivecontacts 84 and 86. The opening of these contacts shuts" down the fourto five inches.

A blockage or interruption of airflow may also occur due to anaccumulation of lint in filter screen 56 impeding the air flow. In thislatter event the machine operator may readily see that the machine isnot operating and that the cycle has not concluded. On inspecting thelint screen 56 and finding it full, the operator would empty the lintfilter and thenreset the machine. i

The other most probable cause of trouble inthe machine is that which mayfollow an accumulation of lint or" other matter the chamber 40. This mayclog drain 62 and cause condensingjliquid to rise within chamber 40.Previously, diaphragm switches responsive to the increase in liquidlevel have beenused as shut-off switches. The operating environment ofsuchswitches is incompatible with uniformity and accuracyof response,for there is at most, an available water head of only The limited headpressure makes it necessary to employ a very sensitive diaphragm switch,and it has been the general experience that such switches .lead totalseindications of difficulty and unnecessary service calls.- Thepresent'invention alleviates the necesdrive motor are then lookedoperated. As motor 50 is accelerated, contacts 86 also close completingthe circuit to the heaters through closed thermostat 90 and timercontacts 92. The heaters heat the circulating air as the a drum. rotatesfora short period hollowing which con tacts 97 close initiating thecondensing action.

As mentioned previously, is circulated by the blower through a closedcycle including'the condensing chamber, inlet duct, heating area,tumbling drum, exhaust duot and hack to the blower. In this way air isheated at the heaters and is passed through the drum which is beingrotated to tumble the wet clothes therein. Heated air contacts thetumbling clothes and absorbs moisture from the clothes. This wet exhaustair leaves the drum throughthe front access opening and enters theexhaust duct 34. The screen 56 catches lint borne in the air and allowsthe moist air to be conducted through blower 36. The air is then emittedthrough duct 38 past thermostat 90' and into the condensing chamber.There, the hot, moist exhaust air meets the spray of cooling water fromnozzles 66 and the moisture condenses out. This condensate is drainedout drain pipe 62 by the action of drain sity of use of a pressurediaphragm and utilizes the high temperature thermostat 104 as the waterlevel sensor. An overfill of Water in the condensing chamber will causea water buildup at least to the lower edge of baffle 72.

Such an overfill will form-Ia barrier covering the free area belowbafile 72 and will block the air how out of the chamber. Blockage ofair, flow will result in an excessively high temperature conditionwatthennostat 104, causing opening ofthe thermostat contacts 104,andsubseq-uent machine shut-off. Thus, the baffle and excessive waterlevel combine to block air flow on'a high'water conditionin thecondensing chamber. o

It should be noted that the water retentive capacity of chamber 40 issufliciently great that following amalfunotioning, shut-oh andsubsequent reset, the chamber can retain the excess of water withoutflooding. On reset, the condenser solenoid does not operate for a periodduring which heated is circulated and if prior'to the conclusion of thisperiod the blockage has not corrected itself, the machine will continueto overheat and shut oil.

To allow service accessibility to the drain pump and 7 condensingchamber, a small [access opening 108 has been provided in the side ofthe cabinet wall asshown in FIG. A door (not shown) may be hinged orheld by screws to cover the opening in .any suitable manner allowingeasy removal. Oniiremoval of the door from opening 108, the condenserchamber 40 may be approached easily. The condenser chamber contains adoor 110, secured in suitable fashion to the chamber wall to seal thechamber firom leaks. The lower extent of this door optimally should beabove the lowerlevel of baffle 72 to prevent wa ter overflow on removalof door 110 in case of trouble. I This condenser door 110 may be reachedfollowing removal: of cabinet door and removed to allow the d'arin pipe62 tobecleared of obstructions when necessary. Needless to say, both theinner and outer doors should be replaced completely prior tore-operation of the machine.

7 While there has been described what is at present considered to hemepreferred embodiment of the invention,

it will be understood that various modifications may be made therein,and it is intended to cover in the appended claims all suchmodifications as fall within the true spirit and scope of 1 theinvention.

What is claimed is: a

1; A laundry dryer comprising an external casing having a loadingopening in a wall thereof, 7

a clothes-receiving drum mounted for rotation within said casing, afiront wall of said drum having an opening communicating with saidloading opening and a rear wall provided with a plurality of air inletOrr-wings, v

structure within said casing forming a heating chamber openly facingsaid drum rear wall,

electric resistance heating means in said chamber, a

structure providing a duct communicating between the front end portionofsaid drum and said heating chamber, said duct including a horizontallyextending condensing chamber having a bottom wall configurated to fiorina sump communicating with an outflow pipe,

means comprising a cold water inletpipe and at least one spray nozzlearranged to discharge cold water into said condensing chamber,

a normally closed valve in said inlet pipe,

a solenoid arranged on said valve, 1

a blower for enforcing air flow in a closed circuit sequentially throughsaid heating chamber, said drum, and said condensing chamber, in aquantity sufiicient 'to maintain air temperature in said heatingchamberbelow :a predetermined minimum,

a motorfor drivingsaid blower,

a bathe in said condensing chamber arranged rupt said air circulationupon a predetermined increase in water level within said chamber,

- an electric circuit common to said solenoid and said motor forenergizing the same,

7 means fior completing said last-named circuit,

I and athermostat responsive to air temperature in said heating chamberto open-said circuit upon sensing v a temperature above saidpredetermined minimum, wherebysaid water inlet valve will close and saidmotor will be deenergized- 2. Alaundry dryer comprising an externalcasing having a loading opening in a wall thereof,

- -a clothes-receiving drum mounted for rotation within said casing,said drum having at one end an opening communicating with said loadingopening and at its opposite end being provided with a plurality of airinletopenings, structurewithin said casing forming a heating chamberopenly facing said air inlet openings, 7

electric resistance heating means in said chamber, structure providing aduct communicating between the front end portion of said drum and saidheating energization thereof to opento interchamber, said duct includinga condensing chamber disposed wholly below said heating chamber, saidcondensing chamber having a bottom wall configurated to form a sumpcommunicating with an outflow means comprising a cold water inlet pipeand at least one spray nozzle arranged to discharge cold Water into saidcondensing chamber,

a normally closed valve in said inlet pipe,

a solenoid arranged on energization thereof to open said valve,

a blower ,cfor enforcing air flow in a closed circuit sequentiallythrough said heating chamber, said drum, and said condensing chamber, ina quantity suliicient to maintain air temperature in said heatingchamber below a predetermined minimum,

a motorfor driving said blower,-

a bathe extending across said condensing chamber intermediate the inletand outlet ends thereof, said baffle terminating above said chamberbottom Wall to interrupt said air circulation upon a predeterminedincrease in water level said condensing chamber,

an electric circuit oommonto saidsolenoid and said motor forenengizingthe same,

means for completing said circuit,

and a thermostat disposed in said heating chamber above the heatingmeans therein to open said lastnamed circuit upon sensing a temperaturein said chamber above said predetermined minimum, whereby said waterinletvalve will close and said motor will be deenergized.

3. A laundry dryer comprising an external casing having a loadingopening in a .wall thereof,

a clothes-receiving drum mounted for rotation within said casing, afrontwall of said drum having an opening communicating I with said loadingopening and a rear wall provided with a plurality of air inlet openings,

structure within said casing forming a heating chamber openly facingsaid drum rear wall,

electrically activated means for increasing the air temperature in saidheating chamber,

, structure providing a ductcommunioating between the front end portionof said drum and said heating chamber, said duct including a condensingchamber having a bottom wall coniigurated to form a sump communicatingwith an outflow pipe,

means comprising a cold Water inlet pipe and at least one--spray nozzlearranged todischarge cold water ',into said condensingJchambe-r, I

' a normally closed valve in said inlet pipe,

a solenoid arranged on energization thereof to open said valve,

a blower for enforcing air flow in a closed'circuit sequentially throughsaid heating chamber, said drum, and saidcondensing chamber, in aquantity suflicient to maintain air temperature in said heating chamberbelow a predetermined minimum,

an energizing circuit for said electrically activated air heating means,

a motor for driving said blower,

a switch in said energizing circuit, said switch being arranged foroperation by said motor from a normally open to a closed circuitcondition as said motor reaches a predetermined speed, i

a baffie in said condensing chamber arranged to interrupt said aircirculation upon apredetermined increase in water level within saidchamber,

an electric circuit common to said solenoid and said motor forenergizing the same,

means for completing said circuit,

and a thermostat responsive to air temperature in said heating chamberto open said last-named circuit upon sensing a temperature above saidpredetermined minimum, whereby said water inlet valve will close aclothes-tumbling drum therein,

duct means establishing a recirculating air-flow circuit i which air isdrawn from said drum and returned thereto,

said air-flgow duct means including a condensing chamber having airinlet and air outlet passages com municating with said drum,

means for enforcing air flow through said duct means,

electric resistance means for adding heat to the recircu- 'lating airprior to its return to said drum,

means including a water spray device adapted to be connected to a coldwater supply for introducing a cold water spray into the air traversingsaid eondensing chamber,

means communicating with said chamber for removing water therefrom,

imperforate bafile means extending across the interior of said chamberupstream of the air outlet passage thereof, said baffle meansterminating above the base of said chamber to provide therewith anair-flow passage only so long as said bafile is not immersed in Waterwithin said chamber,

solenoid operated valve means for controlling water flow to said spraydevice,

an energy circuit for said valve means,

and a thermostatin said energy circuit, said thermostat being disposedin said air flow circuit and responsive to a predetermined increase intemperature of air therein to interrupt said energy circuit. I

References Cited in the file of this patent UNITED STATES PATENTS2,577,104 Butler Dec. 4, 1951 2,644,245 Hammell July 7, 1953 2,654,160Peterson Oct. 6, 1953 2,680,914 Smith June 15, 1954 2,722,057 Pugh -2-NOV. 1, 1955 2,858,621 McMillan NOV. 4, 1958 2,878,580 Hughes Mar. 24,1959

4. A CONDENSING TYPE CLOTHES DRYER, COMPRISING: A CABINET, ACLOTHES-TUMBLING DRUM THEREIN, DUCT MEANS ESTABLISHING A RECIRCULATINGAIR-FLOW CIRCUIT IN WHICH AIR IS DRAWN FROM SAID DRUM AND RETURNEDTHERETO, SAID AIR-FLOW DUCT MEANS INCLUDING A CONDENSING CHAMBER HAVINGAIR INLET AND AIR OUTLET PASSAGES COMMUNICATING WITH SAID DRUM, MEANSFOR ENFORCING AIR FLOW THROUGH SAID DUCT MEANS, ELECTRIC RESISTANCEMEANS FOR ADDING HEAT TO THE RECIRCULATING AIR PRIOR TO ITS RETURN TOSAID DRUM, MEANS INCLUDING A WATER SPRAY DEVICE ADAPTED TO BE CONNECTEDTO A COLD WATER SUPPLY FOR INTRODUCING A COLD WATER SPRAY INTO THE AIRTRAVERSING SAID CONDENSING CHAMBER, MEANS COMMUNICATING WITH SAIDCHAMBER FOR REMOVING WATER THEREFROM,